Moyamoya disease

Moyamoya disease is a chronic cerebrovascular disorder with spontaneous occlusion (stenosis) of terminal part of internal carotid arteries bilaterally, along with angiogenesis at the base of the brain. Moyamoya disease is found predominantly among those of Japanese and Korean descent; however cases now have been described worldwide. Moyamoya has a bimodal age distribution, as it also affects children less than age 10 year old and adults in their mid-40s. When occurring in childhood, the clinical presentation is generally milder, with ischemic symptoms predominating. Intracranial hemorrhage in patients with moyamoya disease is common in adults. Digital subtraction cerebral angiography is the gold standard for diagnosis. Moyamoya disease is treated primarily by surgical attempts at revascularization. Surgical treatment of patients with moyamoya uses the external carotid artery as a source of new blood flow to the ischemic hemisphere. Surgical treatment methods are direct and indirect revascularization procedures or a combination of the two. In direct revascularization, a branch of the external carotid artery, the superficial temporal artery is directly anastomosed to a cortical artery. Indirect revascularization involves a variety of indirect attempts at promoting revascularization over large areas of brain that in weeks provide collateral circulation.